Thermostatic control of seal leg valves



May 27, 1952 l.. w. HEAD THERMOSTATIC CONTROL OF SEAL LEG VALVES 2'SHEETS-SHEET 2 Filed May 18, 1949 JNVENTOR. agri /Zfafz had lAGE/vromrZR/ver l BY Patented May 27, 1952 l THERMOSTATIC CONTROL OFSEAL LEG VALVESI Lloyd Wilson Head, Beaumont, Tex., assgnor toSocony-Vacuum Oil Company, Incorporated, New York, N. Y., a corporationof New York Application May 18, 1949, Serial No. 93,996

This invention is directed to a method and apparatus for safeguarding.against the escape of fluids from a Vessel in which the fluids arecontacted with a continuously-flowing hot, particle-form, contact massat pressures above that of a supply hopper located above. An example ofthis type of process is the catalytic cracking of hydrocarbons in whicha particle-form contact material is passed downwardly through a reactionvessel in the form of a gravitating bed, said column extending above thereaction vessel through a suitable feed conduit into a supply hopper.Selected hydrocarbons, usually in the nature of a gas oil, areintroduced into the vessel in a preheated vapor state, wherein theycontact the particle-form catalyst maintained at conversiontemperatures, in the neighborhood of 8001200 F. The hydrocarbons areconverted under these conditions of temperature and a pressure somewhatabove atmospheric in the presence of the solid adsorbent contact mass,and the converted products are continuously withdrawn from the reactionzone. The catalyst mass usually partakes of the nature of fullers earth,or other natural or treated clays and/or various other syntheticcompounds or associations of alumina, silica or silica and alumina, forexample. Such contact material may desirably fall within the range ofabout 4 to 20 mesh. A small amount of fines formed by attrition of thenormal sized v particles will also be present.

In more complete form, this process is one in which the particle-formmaterial is moved cyclically through two zones. The contact mass isfirst gravitated downwardly through a reaction zone where it iscontacted with hydrocarbon reactants at suitable temperature andpressure to cause conversion to more desirable products. The contactmaterial becomes coated with carbon and carbonaceous material and isthen removed from the reaction zone and transported by bucket elevatorto the top o! a regeneration zone where the contact material issubjected to regeneration by combustion supporting gas, burning thedeposits from the surface of the catalyst. The catalyst, aftergravitating through the re generation zone, is transported to the top ofthe reaction zone, usually by another bucket elevator. It is customaryto supply the catalyst from the tops of the elevators into storagehoppers located above each zone, and then feed the contact materialdownwardly from the hoppers through feed legs into the respective zone.The pressure in the hopper is.usually atmospheric Whereas thev pressurein the'vessel below may be 6 Claims. (Cl. 223-1) approximately 5 poundsabove atmospheric. The feed leg must therefore be suiiiciently long toprovide a head of catalyst sufficient to force catalyst into the vesselagainst this pressure differential. In addition, an inert seal gas isusually admitted to the top of the vessel, flowing upwardly through thefeed leg and out a vent opening in the storage hopper.

This invention is particularly directed to preventing the reactantvapors in the reaction vessel from escaping up through the contactingmaterial feed leg when the ow of contacting material through'the feedleg is interrupted, causing a loss of seal. For a variety of reasons thenormal downward flow of particle-form material in the feed leg isinterrupted, allowing the highly heated, reactant vapors to escape tovarious locations in the apparatus to burn upon contact with air.Dangerous explosions may be encountered in apparatus not constructed towithstand high pressures, or damage may be inflicted to moving parts,such as'elevators, not equipped to operate under such conditions.

The object of this invention is to protect the apparatus from damagecaused by escaping reactant vapors in these instances when the feed legseal is broken, by automatically closing the feed leg just after therupture of the seal. Another object of this invention is to actuate awarning device to indicate the impending rupture of seal in the reactorfeed leg, enabling steps to be taken to prevent the loss of seal, Andstill another object of this invention is to prevent the reactor frombeing partially or completely drained of catalyst when the flow ofcatalyst through the feedleg is interrupted.

These and other objects of the invention will become apparent from thefollowing discussion of the invention.

The invention may be most easily understood by reference to the drawingsattached hereto of which,

Figure 1 is an elevational view showin-g the general arrangement of acyclic hydrocarbon conversion system of the type to which this inventionpertains;

Figure 2 is a vertical view, partially in section, showing in detail theupper section of one of the chambers of Figure 1, the particle-formmaterial feeding means and the application of the apparatus of theinvention thereto;

Figure 3 is a vertical view of one of the vessels of Figure 1 and itsrelated apparatus, showing another embodiment of. the invention. Allthese drawings are highly diagrammatic in form.

l a suitable rate 'controiledjby valve la.

Re'gneratedfcatalyst passes from the lower endv i of chamber 23? viaconduit 2B tol conveyor 30 by particles. f ample, have been found to besatisfactory for this purpose. VIt will be understood that Vthe saidheat transfer @bres-' Referring now to Figure 'I there is shownV acyclic system for 4catalytic conversion of highl boiling hydrocarbonssuch as gas oil fractions to gasoline and other products;

mesh (Tyler screen analysis) catalyst, Vpasses f from a supply hopper Idownwardly through an end of reaction vessel'I2. The catalyst movesdownwardly through vessel I2 as a substantially compact vcolumn whilebeing .contacted Withvhyl l Catalyst in par-V l Y ticle form, VvaryingVin size, for example 4-20- elongated-gravityfeed leg II in to the 'upperY.

action zone.

tained an accumulation of particle-form Contact the conduit 3|. Thecatalyst forms a continuous column, moving down through the feed leg IIinto the reactor I2. The feed leg II delivers di- Y rectly into the headsection 4I of the reactor I2, whichhead section is terminated by plate Eextending horizontally across said head section. Depending from theplate 42 are the openend pipes 43. 'which extend down to the reactor re-Within the Yhead section is mainmaterial from which contact materialiiows drocarbonvapors introduced fromstock prep-j' Ythe lowersection ofvessel I2 Via conduit It.` The gaseousV hydrocarbon products pass from'laration system YI3 of conventionaltyp'e into.

the upper section o f the vessel I2 through con-` duit I5V tothe productrecovery systemjl. The.

escape of hydrocarbons through thegfee'd leg I I is preventedV partiallyby maintaining 'a blanl ket Vof an inertseal gas such as steam ornue gasWithin the upper end of vessel I2 andfp'artially bythe throttling actionof the catalyst '1 l .inijthefeed leg.V The-'sealg'as is 'introducedthroughv conduit I-'LV Spentcatalyst bearing a carbonaceous deposit iiswithdrawn fromthe' lower end of vessel'l2, Vthrough conduit I8 atcatalyst ispurged substantially free of: gaseous' hydrocarbons beforebeing withdrawn from vessel 'I2'byl` means of anjinertpurge gas such asVstearnor- `ue 'gas introduced at 4U. The spentv l Vcatalyst vpasses toconveyor by which it is` conducted to sloping supply duct. 2|wloichsup#` plies catalyst .to the upper section of regeneratorVesself22. "Regenerator vvessel 22 is comprised Vof anfupperf'catalystsurge chamber- Y23 and a1 j Vcornniunicatin'gilower burning chamber 2c.'Air" lower end throughvconduit 25. 'The air movesl upwardly 'through'the columnl of 'gravitating catalyst-particles` in'V burning chamber 23soj' as'toburnoi` the carbonaceous deposit there-` fromga'nd. iswithdrawn near theV upper end of chamber 23 through? conduit 26. VAsuit`v able heat exchange fluidis introduced to heat transfer '.tube's'(not shown) within the chamber f V23 via'cbnduitzt; .The nuidpassesthrough the a i Vheat transfer'A tubes toremovethe excess heat.

of contaminanti combustion from the catalyst and is withdrawn froinfthetubes via conduit-28.

which it is conductedtothe downwardly sloping l 2U' and '30 may beofra'ny! suitable type,` adapted i to transfer'particlefform solids atelevated tem-V peratures withoutfexcessive Yattrition of thegsolidContinuous bucket elevators, Yfor ex' reactor andregeneratorvesselsf mayvary somewhat from Vthe particular construction describedY hereinabove.Y For example, Vthe regenerator may y be of the multifstagetype'comprised of a vertical Y Vseries VVof alternating' burning andcooling zonesj Veach burning zone "having a separate gas inlet f andoutlet and each cooling zone having' av separate s'etof'heat transfertubes therein Vand` separate l extc'ernal manif() lfdin'g4 associatedwith Referring'now to Figure A2 there is shownthe through pipes 1.53v tothe Yreaction zone (not shown) Connected to the topV of the head sectionisrthe pipe I1. The feed leg II is of such lengththatjthehead Vcreatedbythe column .of

contact materialtherein is greater than the pressure differentialbetween the reactor head di and the. hopper- IG. The Ycross sectionoithe .feed leg is made llarge enoughV to permit the desired contactmaterial ow rate.V

At approximately 12 to 24 inches above the bottom of the feed leg II'islocated nthewwall of the feed'leg a temperature responsive ther-mor. s

fmaybe made to operate the valve 49. in rc-v sponse to a predetermineddrop rin temperature in the feedleg II, at thelocation of the thermo@9111318 44. This, in turn, willact to place valve 4S in the. closedpositionr Y Y In normal operation,` a seal gas is introducedv into thehead VVof the reactor-" through'the pipe duct 3|? supplying hopperrIIJ.A The conveyors i.

. .of reactor sea1, 'the 'relay lrismade tof'operate, Y

Y `by suitable-electrical connectioh, a annunciator- Y located in the`controlijoomof'the system.' By.

'I,usualy at a pressure of about 4 to 5y p. s. i.

above atmospheric. The seal gas ows upwardly through the feed-legllvtosthefree space vabove :the catalyst column inthe feed hopper' I0.,which is usually maintained at'atmosphericpressure. The seal `gasescapes throughtheventpipe 5). When a stoppage-occurs;usually in the'upper section of the feed leg" II, the catalystfbelowlV y the .stoppagewill drainfrom the feed?.legfexal 'Y posingithe thermocouple y411/.'There isarapid Vdrop in temperatureat thatv point, which( is'.

used` by the apparatus described aboveto vautomatically close the valve`4B, 'jistlprior'to Ire. moval of the remaining catalyst from the bot;tom'of the feed leg( 'Withutfoatalyst theV feed'leg II, thef'flow ofseal gas' would/not bel sufficient toV prevent reactant fluids fromflowing up from theY react'on zone and. on up the feed leg,V becauseofjthe; largerffree areafin the.' .feed leg available forthefflwofiiuids'when the catalyst is removed. Q 'I l In addition toclosingvalve Atto preventloss observing 'the Ywarnin the operatorissable 'to rapidlyfsh'ut down'l'the; euipmenti 'preventing upperVportionoff the reaction vessel vI2 andthefYV feed hopper I0 and feed legI'I located above the Yreacfztion vesselV I2. "Catalyst vfrom the eleffvater is intrordcceamtgtne hopper 1 0 erfreuen great "serious damagetotheeqnipment. Y v

On, Figure' .3v is; Shown another. embodiment .0f this invention.' yThisviewisavertical'elevation f of the reaction vessel, the hopper and',fe ei leg V located above. andths'vesel.jutletmeansshew belvw-.g As.Apreviouslr. indica sti the Lzcatalrstji from the elevator is fedthrough the conduit 3| to the top of the column of catalyst in thehopper I0. The catalyst gravitates downwardly through the feed leg IIandrreactqr I2, and is removed from the bottom of the reaction vesselI2through the outlet conduit I8. The flow of catalyst through thereactor I2 is normally controlled by the valve I9 inthe outlet conduitI8. In this embodiment of the invention another valve 50 is placed inthe conduit I8, and is maintained in the full open position duringnormal flow of catalyst in the feed leg. A thermocouple 44 is placed inthe feed leg II at a location about I2 to 24 inches above the bottom ofthe feed leg. As previously indicated, when the flow of catalyst throughthe feed leg is interrupted by a stoppage in the feed leg, the catalystlevel drops below the thermocouple and the thermocouple indicates a dropin temperature. This may be used to close valve 44 in the feed leg II,as previously indicated. In addition, however, the drop in temperaturemay be used to trip the relay 5I, which may be used to close the valve50, preventing the removal of any more catalyst from the reactor I2, andthereby preventing the partial or complete removal of catalyst from thereactor I2. There are many obvious reasons why it is undesirable topartially or completely empty the reactor I2 of catalyst. The relay 5I,receiving electrical power from a source not shown, may be used tocontrol a valve 52 in a fluid line 53, which in turn can be used tooperate a iluid operated motor 54. The motor 54 is suitably designed tocompletely close the valve 50. The response from the thermocouple 44 mayalso be used to operate an annunciator, enabling the operator to rapidlyshut down the apparatus and prevent serious damage.

It shall be understood that the details of construction and ofapplication of this invention given hereinabove are intended asexemplary and should not be construed as limiting the scope of thisinvention except as it is limited in the following` claims.

I claim:

1. In a process for contacting fluids under pressure with a continuouslyflowing substantially compact body of partic1e-form, high temperature,solid material, the steps which comprise gravitating said materialdownwardly as a continuous compact column from a storage zone through aconduit to a solid material accumulating zone and thence, at apredetermined rate, to a pressurized reaction zone, introducing an inertseal gas under pressure to said accumulatingy zone, the temperature ofsaid seal gas being maintained below the temperature of said solidmaterial, continually sensing with a temperaturesensitive device thetemperature in the lower portion of the said conduit, and automaticallyclosing the conduit, in response to the temperature sensed by saidtemperature-sensitive device, to prevent the escape of any substantialamount of said fluid through said conduit when the temperature sensed bysaid temperature-sensitive device falls below a predetermined value,said value being in the range between the temperature of the solidmaterial and the temperature of the seal gas.

2. In a process for contacting fluids under pressure with a continuouslyflowing substantially compact body of particle-form, high temperature,solid material, the steps which comprise gravitating said materialdownwardly as a continuous compact column from a storage 6 zone througha conduit to a solid4 material accumulating zone and thence, at apredetermined rate, to a pressurized reaction zone. continuouslywithdrawing particle-form material from an exit in the lower portion ofthe said reaction zone, introducing an inert seal gas under pressure tosaid accumulating zone, the temperature of said seal gas beingmaintained below the temperature of said solid material, continuouslysensing with a temperature-sensitive device the temperature in the lowerportion of said conduit, and automaticallyv closing the conduit and theexit of said reaction zone in response to the temperature sensed by saidtemperature-sensitive device, when the temperature sensed by saidtemperature-sensitive device falls below a predetermined value, saidvalue being in the range between the temperature of the solid materialand the temperature of the seal gas, to prevent the escape of anysubstantiall amount of said uid through said conduit and to prevent thereaction zone frombeing drained of solid material when the flow thereofis interrupted in said conduit. y

3. A vertical vessel for receiving iiuid under pressure, said vesselincluding a solid material accumulating zone and a reaction zonetherebelow and a passage therebetween, a gas supply conduit connected tosaid material accumulating zone for supplying a seal gas thereto, asupply hopper above said vessel to receive hot, particle-form, solidmaterial, the temperature of said seal gas being maintained below thetemperature of said solid material, a solid material supply conduitconnected between said accumulating zone in said hopper to continuouslysupply a gravitating column of said solid material from said hopper tosaid accumulating zone,'an outlet conduit connected to the bottom ofsaid reaction zone to receive said solid material after it hasgravitated therethrough, a temperaturesensitive device .located in thelower section of said solid material supply conduit to sense thetemperature therein', a valve in said solid material supply conduit tocontrol the ow of said solid material through said conduit, meansoperatively connecting said temperature-sensitive device and said valveto operate said valve in response to the temperature sensed by saidtemperature-sensitive device, to close said valve when temperaturesensed by said temperaturesensitive device falls below a predeterminedvalue, said predetermined value being in the range between thetemperature of the solid material and the temperature of the seal gas'.

4. A vertical vessel for receiving fluid under pressure, said vesselincluding a solid material accumulating zone and a reaction zonetherebelow and a passage therebetween, a gas supply conduit connected tosaid material accumulating zone for supplying a seal gas thereto, asupply hopper above said vessel to receive hot, particle-form, solidmaterial, the temperature of said seal gas being maintained below thetemperature of said solid material, a solid material supply conduitconnected between said accumulating zone in said hopper to continuouslysupply a gravitating column of said solid material from said hopper tosaid accumulating zone, an outlet conduit connected to the bottom ofsaid reaction zone to receive said solid material after it hasgravitated therethrough, a temperaturesensitive device located in thelower section of said solid material supply conduit to sense thetemperature therein, valves located in said out-

